Modified speed sensor-less grid connected DFIG based wind energy conversion system for decoupled control of active and reactive power

This paper presents the performance study of a speed sensor-less control of grid connected DFIG based variable speed Wind Energy Conversion System (WECS). A new phase locked loop (PLL) based slip speed estimator using rotor current is proposed for speed sensor-less stator field oriented vector control operation of rotor side converter (RSC) to ensure decoupled control of stator active and reactive power while maximizing the power generation at unity power factor under varying wind speed. The estimated slip speed is used for back emf compensation of rotor current controllers. Simulation has been carried out in MATLAB/ Simulink environment and results show satisfactory operation of the proposed speed sensor-less DFIG based variable speed WECS.